https://streetcomplete.app/

Lots of users of StreetComplete in the UK. It’s good fun.

It’s nowhere close to Street view’s quality or quantity, but there is Panoramax

You could look through issues raised by other and try to replicate it. Offer your voice to confirm that there is a concrete issue, logs, steps to replicate, etc. As your familiarity builds you’ll be able to identify likely areas in the code causing the issue. This really helps others to implement the fix and before long, you’ll be the one fixing it yourself.

Also, look at codetriage.com.